The goal is to identify genes which influence blood pressure and thus are responsible for the development of hypertension in Mexican American families. Because of the importance of insulin resistance in hypertension, as well as the high prevalence of insulin resistance in the Mexican American population, the study places great emphasis on examination of insulin resistance as an intermediate phenotype in this ethnic group. Patients are recruited at USC and lymphoblastoid cell lines for DNA studies are established in the Tissue Culture Facility here at Cedars-Sinai.